1. Field of the Invention
The invention relates to a pressure container that is provided in, for example, a fuel cell system, and more specifically, to a pressure container in which a metal socket contacts a CFRP (Carbon Fiber Reinforced Plastics) layer.
2. Description of the Related Art
An example of the aforementioned type of the pressure container is described in Japanese Patent Application Publication No. 7-310895 (JP-A-7-310895). The pressure container described is a tank in which a liner layer made of polyethylene resin is reinforced by applying a CFRP layer to an outer surface of the liner layer. An opening of the tank is provided with a socket made of aluminum alloy.
Generally, when conductors, which have mutually different electrode potentials, contact each other under a condition, e.g. a wet condition, galvanic corrosion occurs. The galvanic corrosion may also be referred to as contact corrosion, potential difference corrosion, or stray current corrosion. If the pressure container is placed in such a wet condition, an electric cell may be formed. In the electric cell, the aluminum alloy, which forms the socket, serves as a negative terminal, and the carbon, which forms the CFRP layer, serves as a positive terminal. In this case, the socket, which has lower electric potential, may corrode.
In order to prevent the aforementioned corrosion, in the pressure container described in Japanese Patent Application Publication No. 7-310895 (JP-A-7-310895), the socket is provided with an electrical insulating layer by applying an electrical insulating resin to the socket, or attaching an electrical insulating adhesive tape on the socket.
However, the process to form the aforementioned electrical insulating layer is complicated, and moreover, it is difficult to form the electrical insulating layer of entirely uniform thickness, using the methods as described above. Therefore, there has been a demand for improvement of the forming method.